Ideology is the study or science of ideas; otherwise know as the study of common sense. Hegemony is the reification (or the construction, manifestation, and maintenance) of ideology. To explain, ideology is a construction of the Dominant within a group, which can include the Dominant’s mannerisms, dress, etc. Hegemony is then the construction of that construction, i.e. the way the group accepts this ideology. Ideology can have one of three hegemonic responses: oppositional, negotiated, or dominant/hegemonic. This means that one can refuse, justify, or accept the ideology.
We can see instances of ideology and hegemony clearly through the Urinal Game. The first page gives us our ideology, or dominant view, saying, “The object of the game is to test your knowledge of men’s bathroom etiquette. You will be presented with several scenarios. In each one you must select the proper urinal to use.” The ideology presented here is proper etiquette for using the men’s bathroom. You take part in the hegemonic process by actually choosing the urinal. By playing the game and choosing a urinal you are negotiating your view on the ideology of bathroom etiquette. If you choose the “correct” urinal, you are choosing with the dominant group, thus choosing a hegemonic view. If you choose an “incorrect” urinal, you are making an oppositional choice, choosing the not accept the ideological indicators of your choice. For example, in the game there is a question about where you would stand if the situation looked like this:

Unless you pick the urinal next to the two men on the right, the ideological view is that you are “pairing up” with the bigger man.

This means that by taking the oppositional view, the dominant would be questioning your sexuality, and thus your part of “society.”